Radio frequency identification (RFID) is a system that reads data from a RF tag (or tag) and/or writes data to a tag that is present in a radio frequency field projected from a RF reader. A RF reader may read data from a tag and/or write data to a tag. Data on a tag may be contained in one (1) or more bits for the purpose of providing identification and other information relevant to the object to which the tag is attached. RFID incorporates the use of electromagnetic or electrostatic coupling in the radio frequency portion of the spectrum to communicate to or from a tag through a variety of modulation and encoding schemes.
A RF tag works conventionally by first recording or “burning in” identification or other data on the tag. Thereafter, the tag sends the recorded identification or other information to a RF reader. A particular advantage of RF tags over bar code, optical characters and magnetic storage (such as the magnetic strip on many credit cards) is that the RF tag does not require physical contact, or as is the case with optical character and bar code readers, line of sight, between the tag and the reading device to be read.
The RF tag memory may comprise read-only (ROM), random access (RAM) and non-volatile programmable memory for data storage depending upon the type and sophistication of the tag. The ROM-based memory is used to accommodate security data and the tag operating system instructions which, in conjunction with the processor or processing logic, deals with the internal “house-keeping” functions such as response delay timing, data flow control and power supply switching. The RAM-based memory is used to facilitate temporary data storage during tag interrogation and response. The non-volatile programmable memory is used to store the tag data and needs to be non-volatile to ensure that the data is retained when the tag is in its quiescent or power-saving “sleep” state. The non-volatile programmable memory may take various forms, electrically erasable programmable read only memory (EEPROM) being typical. Those of ordinary skill in the art will understand that the non-volatile programmable memory may also be flash memory (sometimes called “flash RAM”), which is a type of constantly-powered nonvolatile memory that can be erased and reprogrammed in units of memory called blocks. Flash memory is a variation of EEPROM which, unlike flash memory, is erased and rewritten at the byte level, which is slower than flash memory updating.
Depending upon the type of memory a RF tag contains, the data carried by the tag may be read-only, write once read many (WORM), or read/write. Read-only tags are typically low capacity devices programmed at source (factory programmed), usually with an identification number. WORM tags are user programmable (field programmable) devices. Read/write tags are also user-programmable but allow the user to change data stored in a tag.
Data storage devices such as controllers, drive trays, and the like, are conventionally manufactured by a company for an OEM (original equipment manufacturer) customer. It is often a labor intensive and time consuming process for the manufacturer to assemble, select, track, log, and maintain data storage devices. Thus, it would be desirable to provide a method and apparatus for automatically tracking and communicating data storage device information using RF tags.